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Quarrying Techniques - The Quarry and Blasting

the workers the quarry and blasting
working the slate mechanisation

A slate mill (It is very important to bear in mind that since the quarrying was a Welsh language industry, the translations into English are only meant to give an idea of the meaning of the original. These English versions are modern literal translations. It is important to know that the terminology did vary to some extent from area to area. The terms used here are in the main from the Llanberis area.)


It is claimed that it was Richard Pennant, the first Lord Penrhyn, who was responsible for the idea of working his quarry using ponciau (galleries) linked to other ponciau with bariau (rails) running down the gelltydd (slopes) from one bonc (gallery) to the other for the car cyrn (lit. horned cart a cart with two iron bars at the front to prevent the load of pileri (pillars) and clytiau from falling off.) In some quarries, a blondin or winsh (aerial ropeways) were used, (so named after Blondin the great tight rope walker.) This wire rope ran above the quarry or sinc to lift loads of rubble or slate. Steam power was used to work these before the advent of electricity. All of the ponciau would be given names of a most interesting character like Abyssinia, California, Giarat, New York, Edward Jones, Robin Dre, Ruban Glas and Wembley to note but a few.


Notice that Dinorwig Quarry applying for a licence to store gunpowder, 1874.Powdwr Du (Gunpowder) was used every time since dynamite or gelignite would shatter the slate. The gunpowder was stored in the ty powdwr or cwt powdwr, (magazine) and before entering one had to wear copper soled clogs to lessen the danger of striking a spark. A bag powdwr (lit. powder bag) made of cloth or rubber was used to carry the gunpowder to the quarry face for blasting. Of course, dynamite or gelignite was used to blast away rubble to get at the slate.

Before the age of pneumatic drills the jympar (lit. jumper, a long weighted rod [usually around 2m, but could be longer]. It was used repeatedly thrusting to bore a shot hole.) About 15cms from one end is a ball of iron to produce extra weight. The jympar is used, by thrusting its short end, until the iron ball reaches the mouth of the shot hole. It is then reversed and thrust repeatedly again until reaching the iron ball for the second time. Sometimes powdwr du is placed in fissures instead.

Great care must be taken to powdro (lit. powder) properly, knowing exactly how much powder to use, but also how much stamping is required to loosen the rock safely and not cause injury to anybody. If proper care is not taken the (hole can fire) – twll yn tanio, causing possible severe injury. Saethu (lit. firing) can happen five or six times a day at set hours. When the corn (bugle) is sounded all the quarry men go to the caban mochal ffiar, (the cabin to shelter from the fire.) Three minutes later the corn is sounded again signalling that it is time to light (tanio) the fuse with either a cigarette or match, (never by electricity.) After this, all the tanwyr (lit. firers) run to the cwt mochal ffiar for a smoke or chat. Then after three or four minutes resounding explosions are heard throughout the quarry and the sound of tons of rock falling to the base of each bargen whilst mwg cur yn y pen (lit. headache smoke) covers everything and everywhere. Each quarry man has an unexplainable ability to recognise his own particular explosion. Eight minutes after the first firing call the corn heddwch (lit. peace bugle) is sounded to signify that the firing session is over.

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